homemade emergency light-custom mag

i just made myself a ridiculously long lasting, very very dim maglite build. its a 2d direct drive maglite to a sscp4 led. wow. took a walk with it on a dark night and it will help you avoid puddles, and does make a good night light for walking around house and not waking up the wife. however, if i were to do it again, i would make sure to get a lower vf so it would be a little brighter on 2.4volts.

Why not run alkalines? You'd get 3V and it would still run for years.

I built a little box light with two D alkalines and an old Cree, and on direct drive it only pulled something like 100mA. According to Energizer's specs, thats like 15 hours.

15 hrs. i would have thought it would run for much much longer than that. if it was just 1000 mah batteries, they should run for 10 hrs. aren't energizer d cells more like 12000 or more under low drain? that would be 120 hr runtime!!!

Energizer D PDF

Norm

I run a 2D Brinkmann Digital Dimming light on low (draws about 60mA) with 10000mAH NiMH cells as a night light. It is recharged each week after running continuously for 168 hours. Best of all, it cost $7.98 on clearance at Target a couple of months ago.

jasonsmaglites said:

15 hrs. i would have thought it would run for much much longer than that. if it was just 1000 mah batteries, they should run for 10 hrs. aren't energizer d cells more like 12000 or more under low drain? that would be 120 hr runtime!!!

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Good catch. Apparently math is beyond me some days.

Based on the chart posted, an Energizer D battery would last ~160 hours. It would dim down in the last part of that, but it wouldn't matter at that point.

jasonsmaglites said:

15 hrs. i would have thought it would run for much much longer than that. if it was just 1000 mah batteries, they should run for 10 hrs. aren't energizer d cells more like 12000 or more under low drain? that would be 120 hr runtime!!!

Click to expand...

Good catch. Apparently math is beyond me some days.

Based on the chart posted, an Energizer D battery would last ~160 hours. It would dim down in the last part of that, but it wouldn't matter at that point.

You can't calculate runtime based on that chart, as the battery voltage drops the direct drive current drops quite steeply too. Individual specimens of LED will totally stop conducting at different minimum voltages but it'll be somewhere in the 2.n volt range leaving a fair amount of battery capacity unusable... so there are two divergent factors but all in all it will probably glow pretty dim for hundreds of hours though not enough light to use for walking around most of that time.

If you're going to drive at such low currents you could put the high powered LED to a better use and just replace it with a 1/2W or 1W LED in instead.

I have a 3D dorcy 1watt LED and on used 1v D cells it puts out 60-80ma and bouncing off the ceiling lights up a room nicely but when alkalines get that low chances of leakage goes way up. I have had too many batteries stored in lights set aside for emergencies leak on me that I have pulled the batteries out of almost every one of them.

J_C said:

If you're going to drive at such low currents you could put the high powered LED to a better use and just replace it with a 1/2W or 1W LED in instead.

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are you worried about my finances or just sad to see a good led go to waste, lol. actually i eventually planned on taking the heatsink assembly out and putting it into a 3d mag, or adding a driver for modes and boost.

im thinking about building another one of these and using a lower vf led. my assumption is that it will be brighter dd on 2d's that way. its expecting lower voltage so i wont be underdriving it as much. am i correct? if so, where do i find the lowest vf led for it? is 3.25-3.5 the bin to go with for another 2d build?

I have some pretty newly manufactured warm white Crees with Vfs of about 3.0V at 350mA. I assume SSC does/will have access to those dies.

I used a micropuck in a 2C and I get about 12 hours, most of that time spent running at well above the initial brightness of a stock incan mag on fresh cells.

jasonsmaglites said:

are you worried about my finances or just sad to see a good led go to waste, lol. actually i eventually planned on taking the heatsink assembly out and putting it into a 3d mag, or adding a driver for modes and boost.

im thinking about building another one of these and using a lower vf led. my assumption is that it will be brighter dd on 2d's that way. its expecting lower voltage so i wont be underdriving it as much. am i correct? if so, where do i find the lowest vf led for it? is 3.25-3.5 the bin to go with for another 2d build?

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LOL... shame to see the LED not reach it's full potential.

Yes an LED with a lower forward voltage will be brighter (and/or use multiple dies in parallel), but to get the lowest possible you may have to sort through several or ask around if anyone has such a specimen they'll part with.

actually i just realized i think im using an "h" bin 3.0-3.25vf so its already pretty low. unless there is a g bin out there, im about as bright as its gonna get.

jc, you would die if you saw my other red 2d mag. it has a $120 ek3 drop in with 3 mce's (12 dies in all) under driven by 2d's. its only about 3 times as bright as this other light, lol. (preparing for flogging)

So they're kinda like short beat-sticks that glow. :whoopin:

... guess it wouldn't be any fun if all our flashlights were the same.

jasonsmaglites said:

actually i just realized i think im using an "h" bin 3.0-3.25vf so its already pretty low. unless there is a g bin out there, im about as bright as its gonna get.

jc, you would die if you saw my other red 2d mag. it has a $120 ek3 drop in with 3 mce's (12 dies in all) under driven by 2d's. its only about 3 times as bright as this other light, lol. (preparing for flogging)

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H bin lux? I wonder if later bin crees and Seoul emitters would be brighter even with a higher vf due to efficiency